Given the triangle below, Which of the following equations correctly represents the relationship between a,b and c

Answer:
Option D is correct.
Step-by-step explanation:
We are given with a right angled triangle.
Measurement of sides of triangle are a , b , c
and measure of ∠C is 90°
We know that we have a relationship between sides and an angle opposite to a side.
This relation is given by LAW OF COSINES.
In given triangle and using law of cosines, we have
b² = a² + c² - 2ac cos B
a² = b² + c² - 2cb cos A
c² = a² + b² - 2ab cos C ⇒ c² = a² + b² - 2ab cos(90°)
Therefore, Option D is correct.